Effects of commonly used chronic medications on the outcomes of ipilimumab therapy in patients with metastatic melanoma.

e21038 Background: Ipilimumab can induce long-term survival in up to 20% of patients with metastatic melanoma, however response comes with high rates of immune-related adverse events (irAEs). Concurrent chronic medications may impact the patient’s immune system, possess anti-melanoma properties, and potentially affect clinical outcomes (efficacy and/or toxicity). This retrospective study sought to describe the influence of 12 classes of concomitant chronic medications used by metastatic melanoma patients undergoing therapy with ipilimumab. Methods: Retrospective study of 159 adults who received ipilimumab for metastatic melanoma at Mayo Clinic in Rochester, MN from March 1, 2011 through December 31, 2014. Data on patient characteristics, best tumor response, irAEs, progression, death, and use of chronic medications (statins, metformin, beta blockers, ACE/ARBs, calcium channel blockers, aspirin, NSAIDs, H1 and H2 receptor antagonists, proton pump inhibitors, antidepressants, and vitamin D supplements) were abstracted from the electronic medical record. For the analysis of best tumor response and irAEs, a case-control analysis was employed. Overall survival (OS) and progression-free survival (PFS) were evaluated using the Kaplan Meier method and Cox Proportional Hazard modeling. Results: Of the 12 concomitant medication classes, only proton pump inhibitors (PPIs) were found to have an increased odds of experiencing a partial response (PR) or complete response (CR) to ipilimumab (OR, 3.73; CI 1.26-11.04; p = .02). While not significant, PPI use trended towards improved OS and PFS (HR, 0.44; CI 0.17-1.15; p = .09; and HR, 0.6; CI 0.34-1.06; p = .08; respectively). Likewise, H2 antagonist use may result in an increased odds of PR or CR (OR, 5.27; CI 0.99-28.1; p = .05). No medication class was associated with increased risk of grade 3/4 irAEs. Conclusions: Patients on PPIs may be more likely to experience a PR/CR following ipilimumab therapy. Due to the small sample size and retrospective nature of this work, these finding are only descriptive and support further study. Other classes of chronic medications did not produce statistically significant effects for any of the measured outcomes.